Improvement in dentists  stools



l. W. LYON.

YDentists Stools. f

No. 135,435. Paten-fed Feb.4,1873.

AM. PHO ra-umasmm/c ca me (ossamvz's Pnacess) NITED STATES PATENT rrIoE.

ISRAEL W. LYON, OF BROOKLYN, NEW YORK.

IMPROVEMENT IN DENTISTS STOOLS.

l Specification forming part of Letters Patent No. 135,435, datedFebruary 4, 1873.

To all whom it may concern:

Be it known that I, ISRAEL W. LYON, of Brooklyn, in the county of Kingsand Sta-te ot' New York, have invented certain new and usefulImprovements in Stoolfor Dentists, 85o., and I do Vhereby declare thatthe following is a full, clear, and exact description thereof, that willenable others skilled in the art to which it'appertains to make and usethe greater portion of the time; and it consists in` the peculiarconstruction and arrangement of parts whereby the seat may be readilyadjusted to any desired height and inclined at any desired angle withoutdanger of upsetting the stool, and placing it in such a position th atthe person may rest upon or bear against it, thereby taking a part ofthe weight of the body off the feet.

In the accompanying drawing, Figure l is a side view of my invention.'Fig. 2 is a central vertical section.

A represents a base or platform of cast-iron or other suitable material.It is concavo-convex in form, and maybe circular in its outline, orornamented in any suitable manner. In the center of the base A, eithercast with it or attached afterward, is a ball, B, with a double-conicalvertical aperture, b b, through its center. G is a metallic tube, havinga screw-thread on its lower portion, and a collar, c, surrounding itnear its lower end. The collar c may be formed with the tube or attachedafterward, as ma-y be desired. D is a concavoconvex washer, whichsurrounds the tube O below the collar c and above the ball B. Ifdesired, it may be formed with or rmly attached to the tube C, insteadof being a loose washer. E isa concavoconvex nut, formed withV ascrewthread corresponding with the thread on the lower end of the tube.At the upper end of the tube O is an enlargement or collar, from whichproject two lugs, in which is pivoted a cam'lever, F, which may haveratchet-teeth on the extreme end of its short arm. Immediately under thelever F, and pivoted to the tube C, is a cam or button, G, the object ofwhich is to lock the lever F when in a horizontal position. Instead ofthis button G, the lever F may be held by a spring, or any otherYsuitable device. H is an iron rod, having a longitudinal groove, h,formed on one side for nearly or the whole of its entire length. To theupper end of lthis rod is attached the seat K, which may be of anysuitable form. and construction, and attached in any suitable manner..The rod H slides in the tube O in such a manner as to allow the shortarm of the lever F to engage with the groove. The tube C is attached tothe base by passing it through the aperture in the ball B, and securingit with the nut E.

When it is desired to adjust the height ot' the seat it is raised orlowered to the desired position, the lever F is raised until theratchetteeth on its short arm engage with the groove in the rod H, andthe cam or button G is turned so as to lock the lever F and hold it incontact with the rod H, thus effectually preventing the seat fromfalling. By shortening the long arm of the lever F so as to reduce theweight, and placing a spring insuch a position as to hold it in ahorizontal position, the button Gr may be dispensed with, as, the shortarm of the lever being in the form of a cam and serrated, the weight ofthe person on the seat will serve to prevent it from slipping. When itis desired to change the seat from a vertical to an inclined position,the seat is grasped with the hands and turned so as to unscrew the nut Eon the lower end of the tube. It is `then placed at the desired angle ofinclination and turned so as to vtighten the nut, and is thus securelyheld in position.

This ballandsocket clamp-joint,77 as it may be called, may be placed atany point between `the seat and the base; but the further it is from thebase the greater will be the liability to upset.

Having thus described my invention, .what

I claim as new, and desire to secure by Letters Patent, is-

The tubular support or leg C, rod H with seat K, ratchet-lever F, weightG, or its equivalent, ball B with'double-oonioal aperture b b,washe1' D,nuts E 0,9116. base A, cornbined substantially as and for the purposeset forth.

In testimony that I claim the foregoing have hereunto set my hand this23d day of October, 1872.

ISRAEL W. LYON.

Witnesses:

WELLS W. LEGGETT, EDM. F. BROWN.

